Supro 24 Lite - Power tube test

[bmccowan]

Some of you helped me with the Supro 24 Lite I built into a Hammond AO-39 chassis - many thanks. I thought you might be interested in my power tube tests.
I wired the sockets to accept 6973/6cz5/6cm6 tubes. Keeping all settings the same and using a p-90 pickup guitar, these are my thoughts:
All tubes new - not burned in. vol on about 3
RCA 6973 - nice full sound - less grit than I would expect, but then my ears cannot cannot take the volume this amp needs to reach break-up.
RCA 6cz5 - exactly the same to my ears. And looking closely at the tubes, they look exactly the same except for the pin connections. I know many claim they do not sound as good, but I'm suggesting BS on that.
Sylvania USA 6973 - much smaller bottle. The sound is still really good, but the bass is not as full. Still a very good tube that can be had cheaper than the RCA 6973s.
RCA 6cm6 - these are said to be small bottle 6V6s and with these in the amp sounds like a 6G3 brownface deluxe I built a couple years ago. The sound is "rounder" than any of the other tubes. Sounds better at low volumes I think. The voltage is pushing the max for this tube so I may build a GA-40 type amp with a 5879 preamp from another A0-39 I have, getting the B+ down to 300v.
I do not have and don't plan to buy any current EH 6973s - so I cannot compare those.  So my thought is to keep the RCA 6cZ5s in the amp, and to sell my stash of NOS 6973 when the 401K runs dry.
Sluckey and SnickSound, I'm curious what tubes you have tried in yours.
   

[sluckey]

I'm not a tube roller. I bought a pair of Electro-Harmonix 6973s. The other tubes are NOS military tubes.

[shooter]

I'm not a tube roller

me either, but I do tend to fixate on KT88's

[SnickSound]

I'm not a tube roller. I bought a pair of Electro-Harmonix 6973s. The other tubes are NOS military tubes.

Same here. Sounds good to me. I may try some 6CZ5 at some point.

And yes, this amp needs to be really loud to get some overdrive, not practical live but fun in the studio.